Durable remissions achieved with reinfusion of CD19-directed CAR-T despite failure to induce or maintain B-cell aplasia and single-center experience with reinfusion of tisagenlecleucel.

CD19-directed chimeric antigen receptor T lymphocytes (CAR-T) have led to durable remissions in children with refractory and/or multiply relapsed B-lymphoblastic leukemia. For those who relapse or lose B-cell aplasia post CAR-T, the role of CAR-T reinfusion is unclear. We report two cases of durable remission with tisagenlecleucel reinfusion despite failure to achieve or maintain B-cell aplasia, and compare these cases to six additional children who received multiple tisagenlecleucel infusions at our institution. Our experience suggests that reinfusion is safe and may be a definitive therapy for a small subset of patients. Reinfusion can also reintroduce remission and/or B-cell aplasia, allowing for subsequent therapies.